U.S. patent application number 14/484281 was filed with the patent office on 2015-07-30 for optical imaging lens and electronic device comprising the same.
The applicant listed for this patent is Shih-Han Chen, Yanbin Chen, Jinhui Gong. Invention is credited to Shih-Han Chen, Yanbin Chen, Jinhui Gong.
Application Number | 20150212287 14/484281 |
Document ID | / |
Family ID | 51437399 |
Filed Date | 2015-07-30 |
United States Patent
Application |
20150212287 |
Kind Code |
A1 |
Chen; Shih-Han ; et
al. |
July 30, 2015 |
OPTICAL IMAGING LENS AND ELECTRONIC DEVICE COMPRISING THE SAME
Abstract
An optical imaging lens includes: a first, second, third and
fourth lens element, the first lens element having an object-side
surface with a convex portion in a vicinity of the optical axis,
the second lens element having an object-side surface with a convex
portion in a vicinity of the optical axis, and an image-side
surface with a concave portion in a vicinity of its periphery, the
third lens element having an image-side surface with a convex
portion in a vicinity of the optical axis, the fourth lens element
having an image-side surface with a concave portion in a vicinity
of the optical axis, wherein the optical imaging lens set does not
include any lens element with refractive power other than said
first, second, third and fourth lens elements.
Inventors: |
Chen; Shih-Han; (Taichung
City, TW) ; Chen; Yanbin; (Taichung City, TW)
; Gong; Jinhui; (Taichung City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chen; Shih-Han
Chen; Yanbin
Gong; Jinhui |
Taichung City
Taichung City
Taichung City |
|
TW
TW
TW |
|
|
Family ID: |
51437399 |
Appl. No.: |
14/484281 |
Filed: |
September 12, 2014 |
Current U.S.
Class: |
348/360 |
Current CPC
Class: |
G02B 13/004 20130101;
G02B 13/04 20130101; G02B 9/34 20130101; G02B 7/021 20130101 |
International
Class: |
G02B 7/02 20060101
G02B007/02; G02B 9/34 20060101 G02B009/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2014 |
CN |
201410039550.4 |
Claims
1. An optical imaging lens set, from an object side toward an image
side in order along an optical axis comprising: a first lens
element, an aperture stop, a second lens element, a third lens
element and a fourth lens element, said first to fourth lens
elements having an object-side surface facing toward the object
side as well as an image-side surface facing toward the image side,
wherein: the first lens element has an object-side surface with a
convex part in a vicinity of the optical axis; the second lens has
an object-side surface with a convex part in a vicinity of the
optical axis, and an image-side surface with a concave part in a
vicinity of its periphery; the third lens element has an image-side
surface with a convex part in a vicinity of the optical axis; the
fourth lens has an image-side surface with a concave part in a
vicinity of the optical axis; the optical imaging lens set does not
include any lens element with refractive power other than said
first lens element, second lens element, third lens element and
fourth lens element, in addition, the sum of all three air gaps Gaa
between each lens element from said first lens element to said
fourth lens element along the optical axis, an air gap G23 between
said second lens elements and said third lens element along said
optical axis, a thickness T2 of said second lens element along said
optical axis, and a total thickness ALT of said first lens element,
said second lens element, said third lens element and said fourth
lens element along said optical axis satisfy two relationships
Gaa/G23.ltoreq.1.5, and ALT/T2.ltoreq.6.2.
2. The optical imaging lens set of claim 1, further satisfying the
relationship ALT/Gaa.gtoreq.2.0.
3. The optical imaging lens set of claim 2, wherein a thickness T4
of said fourth lens element along said optical axis satisfies the
relationship ALT/T4.ltoreq.4.5.
4. The optical imaging lens set of claim 1, wherein a distance TTL
between the object surface of the first lens element to an image
plane, and a thickness T3 of said third lens element along said
optical axis satisfy the relationship TTL/T3.ltoreq.9.0.
5. The optical imaging lens set of claim 4, wherein a thickness T4
of said fourth lens element along said optical axis satisfies the
relationship TTL/T4.ltoreq.9.5.
6. The optical imaging lens set of claim 5, further satisfying the
relationship TTL/G23.ltoreq.8.0.
7. The optical imaging lens set of claim 1, wherein a thickness T3
of said third lens element along said optical axis satisfies the
relationship ALT/T3.gtoreq.3.0.
8. The optical imaging lens set of claim 7, wherein a distance TTL
between the object surface of the first lens element to an image
plane, and an air gap G12 between said first lens elements and said
second lens element along said optical axis satisfy the
relationship TTL/G12.ltoreq.55.0.
9. The optical imaging lens set of claim 8, further satisfying the
relationship TTL/Gaa.ltoreq.6.0.
10. The optical imaging lens set of claim 1, wherein a thickness T1
of said first lens element along said optical axis satisfies the
relationship Gaa/T1.gtoreq.1.2.
11. The optical imaging lens set of claim 10, further satisfying
the relationship ALT/T1.gtoreq.3.5.
12. The optical imaging lens set of claim 11, wherein an air gap
G12 between said first lens elements and said second lens element
along said optical axis satisfies the relationship
Gaa/G12.ltoreq.12.0.
13. The optical imaging lens set of claim 1, wherein a thickness T3
of said third lens element along said optical axis satisfies the
relationship Gaa/T3.gtoreq.1.0.
14. The optical imaging lens set of claim 1, wherein a distance TTL
between the object surface of the first lens element to an image
plane, and a thickness T2 of said second lens element along said
optical axis satisfy the relationship TTL/T2.gtoreq.15.0.
15. The optical imaging lens set of claim 1, wherein a distance TTL
between the object surface of the first lens element to an image
plane, and a thickness T1 of said first lens element along said
optical axis satisfy the relationship TTL/T1.gtoreq.7.0.
16. The optical imaging lens set of claim 1, wherein a distance TTL
between the object surface of the first lens element to an image
plane satisfies the relationship TTL/ALT.gtoreq.1.8.
17. The optical imaging lens set of claim 1, wherein a thickness T2
of said second lens element along said optical axis satisfies the
relationship Gaa/T2.gtoreq.3.0.
18. The optical imaging lens set of claim 1, wherein an air gap G34
between said third lens elements and said fourth lens element along
said optical axis satisfies the relationship
ALT/G34.ltoreq.25.0.
19. The optical imaging lens set of claim 1, wherein a distance TTL
between the object surface of the first lens element to an image
plane, and an air gap G12 between said first lens elements and said
second lens element along said optical axis satisfy the
relationship 40.0.ltoreq.TTL/G12.ltoreq.55.0.
20. An electronic device, comprising: a case; and an image module
disposed in said case and comprising: an optical imaging lens set
of claim 1; a barrel for the installation of said optical imaging
lens set; a module housing unit for the installation of said
barrel; a substrate for the installation of said module housing
unit; and an image sensor disposed on the substrate and disposed at
an image side of said optical imaging lens set.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Chinese Application No.
201410039550.4, filed on Jan. 27, 2014.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to an optical
imaging lens set and an electronic device which includes such
optical imaging lens set. Specifically speaking, the present
invention is directed to an optical imaging lens set with shorter
length and an electronic device which includes such optical imaging
lens set.
[0004] 2. Description of the Prior Art
[0005] In recent years, the popularity of mobile phones and digital
cameras makes the sizes of various portable electronic products
reduce quickly, and so does the size of the photography modules.
The current trend of research is to develop an optical imaging lens
set of a shorter length with uncompromised good quality. The most
important characteristics of an optical imaging lens set are image
quality and size.
[0006] Taiwan patent 1254140 discloses an optical imaging lens set
made of four lens elements. But the aperture stop is too small, and
the F# (F-number) is about 4.0, which makes it easy to cause
lacking of the incident light intensity in actual situation.
Besides, the total length of the optical imaging lens set is up to
12 mm or more. Such bulky optical imaging lens set is not suitable
for an electronic device of small size with length less than 10
mm.
[0007] Therefore, how to reduce the total length of a photographic
device, but still maintain good optical performance, is an
important research objective.
SUMMARY OF THE INVENTION
[0008] In light of the above, the present invention proposes an
optical imaging lens set that is lightweight, has shorter total
length, has a low production cost, has an enlarged half of field of
view, has a high resolution and has high image quality. The optical
imaging lens set of four lens elements of the present invention has
a first lens element, an aperture stop, a second lens element, a
third lens element and a fourth lens element sequentially from an
object side to an image side along an optical axis.
[0009] The present invention provides an optical imaging lens set,
from an object side toward an image side in order along an optical
axis comprising: a first lens element, an aperture stop, a second
lens element, a third lens element and a fourth lens element. The
first lens element has an object-side surface with a convex part in
a vicinity of the optical axis; the second lens has an object-side
surface with a convex part in a vicinity of the optical axis, and
an image-side surface with a concave part in a vicinity of its
periphery; the third lens element has an image-side surface with a
convex part in a vicinity of the optical axis; the fourth lens has
an image-side surface with a concave part in a vicinity of the
optical axis; wherein the optical imaging lens set does not include
any lens element with refractive power other than said first,
second, third and fourth lens elements.
[0010] In the optical imaging lens set of four lens elements of the
present invention, an air gap G12 along the optical axis is
disposed between the first lens element and the second lens
element, an air gap G23 along the optical axis is disposed between
the second lens element and the third lens element, an air gap G34
along the optical axis is disposed between the third lens element
and the fourth lens element, and the sum of total three air gaps
between adjacent lens elements from the first lens element to the
fourth lens element along the optical axis is Gaa,
Gaa=G12+G23+G34.
[0011] In the optical imaging lens set of four lens elements of the
present invention, the first lens element has a first lens element
thickness T1 along the optical axis, the second lens element has a
second lens element thickness T2 along the optical axis, the third
lens element has a third lens element thickness T3 along the
optical axis, the fourth lens element has a fourth lens element
thickness T4 along the optical axis, and the total thickness of all
the lens elements in the optical imaging lens set along the optical
axis is ALT, ALT=T1+T2+T3+T4. In addition, the distance between the
object-side surface of the first lens element to an image plane
along the optical axis is TTL, namely the total length of the
optical imaging lens set.
[0012] In the optical imaging lens set of four lens elements of the
present invention, the relationship Gaa/G23.ltoreq.1.5 is
satisfied.
[0013] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/T2.gtoreq.6.2 is
satisfied.
[0014] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/Gaa.gtoreq.2.0 is
satisfied.
[0015] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/T4.ltoreq.4.5 is
satisfied.
[0016] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/T3.ltoreq.9.0 is
satisfied.
[0017] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/T4.ltoreq.9.5 is
satisfied.
[0018] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/G23.ltoreq.8.0 is
satisfied.
[0019] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/T3.gtoreq.3.0 is
satisfied.
[0020] In the optical imaging lens set of four lens elements of the
present invention, the relationship 40.0.ltoreq.TTL/G12.ltoreq.55.0
is satisfied.
[0021] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/Gaa.ltoreq.6.0 is
satisfied.
[0022] In the optical imaging lens set of four lens elements of the
present invention, the relationship Gaa/T1.gtoreq.1.2 is
satisfied.
[0023] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/T1.gtoreq.3.5 is
satisfied.
[0024] In the optical imaging lens set of four lens elements of the
present invention, the relationship Gaa/G12.ltoreq.12.0 is
satisfied.
[0025] In the optical imaging lens set of four lens elements of the
present invention, the relationship Gaa/T3.gtoreq.1.0 is
satisfied.
[0026] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/T2.gtoreq.15.0 is
satisfied.
[0027] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/T1.gtoreq.7.0 is
satisfied.
[0028] In the optical imaging lens set of four lens elements of the
present invention, the relationship TTL/ALT.gtoreq.1.8 is
satisfied.
[0029] In the optical imaging lens set of four lens elements of the
present invention, the relationship Gaa/T2.gtoreq.3.0 is
satisfied.
[0030] In the optical imaging lens set of four lens elements of the
present invention, the relationship ALT/G34.ltoreq.25.0 is
satisfied.
[0031] The present invention also proposes an electronic device
which includes the optical imaging lens set as described above. The
electronic device includes a case and an image module disposed in
the case. The image module includes an optical imaging lens set as
described above, a barrel for the installation of the optical
imaging lens set, a module housing unit for the installation of the
barrel, a substrate for the installation of the module housing
unit, and an image sensor disposed on the substrate and at an image
side of the optical imaging lens set.
[0032] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 illustrates a first example of the optical imaging
lens set of the present invention.
[0034] FIG. 2A illustrates the longitudinal spherical aberration on
the image plane of the first example.
[0035] FIG. 2B illustrates the astigmatic aberration on the
sagittal direction of the first example.
[0036] FIG. 2C illustrates the astigmatic aberration on the
tangential direction of the first example.
[0037] FIG. 2D illustrates the distortion aberration of the first
example.
[0038] FIG. 3 illustrates a second example of the optical imaging
lens set of four lens elements of the present invention.
[0039] FIG. 4A illustrates the longitudinal spherical aberration on
the image plane of the second example.
[0040] FIG. 4B illustrates the astigmatic aberration on the
sagittal direction of the second example.
[0041] FIG. 4C illustrates the astigmatic aberration on the
tangential direction of the second example.
[0042] FIG. 4D illustrates the distortion aberration of the second
example.
[0043] FIG. 5 illustrates a third example of the optical imaging
lens set of four lens elements of the present invention.
[0044] FIG. 6A illustrates the longitudinal spherical aberration on
the image plane of the third example.
[0045] FIG. 6B illustrates the astigmatic aberration on the
sagittal direction of the third example.
[0046] FIG. 6C illustrates the astigmatic aberration on the
tangential direction of the third example.
[0047] FIG. 6D illustrates the distortion aberration of the third
example.
[0048] FIG. 7 illustrates a fourth example of the optical imaging
lens set of four lens elements of the present invention.
[0049] FIG. 8A illustrates the longitudinal spherical aberration on
the image plane of the fourth example.
[0050] FIG. 8B illustrates the astigmatic aberration on the
sagittal direction of the fourth example.
[0051] FIG. 8C illustrates the astigmatic aberration on the
tangential direction of the fourth example.
[0052] FIG. 8D illustrates the distortion aberration of the fourth
example.
[0053] FIG. 9 illustrates a fifth example of the optical imaging
lens set of four lens elements of the present invention.
[0054] FIG. 10A illustrates the longitudinal spherical aberration
on the image plane of the fifth example.
[0055] FIG. 10B illustrates the astigmatic aberration on the
sagittal direction of the fifth example.
[0056] FIG. 10C illustrates the astigmatic aberration on the
tangential direction of the fifth example.
[0057] FIG. 10D illustrates the distortion aberration of the fifth
example.
[0058] FIG. 11 illustrates a sixth example of the optical imaging
lens set of four lens elements of the present invention.
[0059] FIG. 12A illustrates the longitudinal spherical aberration
on the image plane of the sixth example.
[0060] FIG. 12B illustrates the astigmatic aberration on the
sagittal direction of the sixth example.
[0061] FIG. 12C illustrates the astigmatic aberration on the
tangential direction of the sixth example.
[0062] FIG. 12D illustrates the distortion aberration of the sixth
example.
[0063] FIG. 13 illustrates a seventh example of the optical imaging
lens set of four lens elements of the present invention.
[0064] FIG. 14A illustrates the longitudinal spherical aberration
on the image plane of the seventh example.
[0065] FIG. 14B illustrates the astigmatic aberration on the
sagittal direction of the seventh example.
[0066] FIG. 14C illustrates the astigmatic aberration on the
tangential direction of the seventh example.
[0067] FIG. 14D illustrates the distortion aberration of the
seventh example.
[0068] FIG. 15 illustrates an eighth example of the optical imaging
lens set of four lens elements of the present invention.
[0069] FIG. 16A illustrates the longitudinal spherical aberration
on the image plane of the eighth example.
[0070] FIG. 16B illustrates the astigmatic aberration on the
sagittal direction of the eighth example.
[0071] FIG. 16C illustrates the astigmatic aberration on the
tangential direction of the eighth example.
[0072] FIG. 16D illustrates the distortion aberration of the
seventh example.
[0073] FIG. 17 illustrates exemplificative shapes of the optical
imaging lens element of the present invention.
[0074] FIG. 18 illustrates a first preferred example of the
portable electronic device with an optical imaging lens set of the
present invention.
[0075] FIG. 19 illustrates a second preferred example of the
portable electronic device with an optical imaging lens set of the
present invention.
[0076] FIG. 20 shows the optical data of the first example of the
optical imaging lens set.
[0077] FIG. 21 shows the aspheric surface data of the first
example.
[0078] FIG. 22 shows the optical data of the second example of the
optical imaging lens set.
[0079] FIG. 23 shows the aspheric surface data of the second
example.
[0080] FIG. 24 shows the optical data of the third example of the
optical imaging lens set.
[0081] FIG. 25 shows the aspheric surface data of the third
example.
[0082] FIG. 26 shows the optical data of the fourth example of the
optical imaging lens set.
[0083] FIG. 27 shows the aspheric surface data of the fourth
example.
[0084] FIG. 28 shows the optical data of the fifth example of the
optical imaging lens set.
[0085] FIG. 29 shows the aspheric surface data of the fifth
example.
[0086] FIG. 30 shows the optical data of the sixth example of the
optical imaging lens set.
[0087] FIG. 31 shows the aspheric surface data of the sixth
example.
[0088] FIG. 32 shows the optical data of the seventh example of the
optical imaging lens set.
[0089] FIG. 33 shows the aspheric surface data of the seventh
example.
[0090] FIG. 34 shows the optical data of the eighth example of the
optical imaging lens set.
[0091] FIG. 35 shows the aspheric surface data of the eighth
example.
[0092] FIG. 36 shows some important ratios in the examples.
DETAILED DESCRIPTION
[0093] Before the detailed description of the present invention,
the first thing to be noticed is that in the present invention,
similar (not necessarily identical) elements are labeled as the
same numeral references. In the entire present specification, "a
certain lens element has negative/positive refractive power" refers
to the part in a vicinity of the optical axis of the lens element
has negative/positive refractive power. "An object-side/image-side
surface of a certain lens element has a concave/convex part" refers
to the part is more concave/convex in a direction parallel with the
optical axis to be compared with an outer region next to the
region. Taking FIG. 17 for example, the optical axis is "I" and the
lens element is symmetrical with respect to the optical axis I. The
object side of the lens element has a convex part in the region A,
a concave part in the region B, and a convex part in the region C
because region A is more convex in a direction parallel with the
optical axis than an outer region (region B) next to region A,
region B is more concave than region C and region C is similarly
more convex than region E. "A circular periphery of a certain lens
element" refers to a circular periphery region of a surface on the
lens element for light to pass through, that is, region C in the
drawing. In the drawing, imaging light includes Lc (chief ray) and
Lm (marginal ray). "A vicinity of the optical axis" refers to an
optical axis region of a surface on the lens element for light to
pass through, that is, the region A in FIG. 17. In addition, the
lens element may include an extension part E for the lens element
to be installed in an optical imaging lens set. Ideally speaking,
no light would pass through the extension part, and the actual
structure and shape of the extension part is not limited to this
and may have other variations. For the reason of simplicity, the
extension part is not illustrated in FIGS. 1, 3, 5, 7, 9, 11, 13
and 15.
[0094] As shown in FIG. 1, the optical imaging lens set 1 of fourth
lens elements of the present invention, sequentially located from
an object side 2 (where an object is located) to an image side 3
along an optical axis 4, has a first lens element 10, an aperture
stop 80, a second lens element 20, a third lens element 30, a
fourth lens element 40, a filter 72 and an image plane 71.
Generally speaking, the first lens element 10, the second lens
element 20, the third lens element 30 and the fourth lens element
40 may be made of a transparent plastic material and each has an
appropriate refractive power, but the present invention is not
limited to this. There are exclusively fourth lens elements with
refractive power in the optical imaging lens set 1 of the present
invention. The optical axis 4 is the optical axis of the entire
optical imaging lens set 1, and the optical axis of each of the
lens elements coincides with the optical axis of the optical
imaging lens set 1.
[0095] Furthermore, the optical imaging lens set 1 includes an
aperture stop (ape. stop) 80 disposed in an appropriate position.
In FIG. 1, the aperture stop 80 is disposed between the first lens
element 10 and the second lens element 20. When light emitted or
reflected by an object (not shown) which is located at the object
side 2 enters the optical imaging lens set 1 of the present
invention, it forms a clear and sharp image on the image plane 71
at the image side 3 after passing through the first lens element
10, the aperture stop 80, the second lens element 20, the third
lens element 30, the fourth lens element 40 and the filter 72.
[0096] In the embodiments of the present invention, the optional
filter 72 may be a filter of various suitable functions, for
example, the filter 72 may be an infrared cut filter (IR cut
filter), placed between the fourth lens element 40 and the image
plane 71. The filter 72 is made of glass, without affecting the
focal length of the optical lens element system, namely the optical
imaging lens set, of the present invention.
[0097] Each lens element in the optical imaging lens set 1 of the
present invention has an object-side surface facing toward the
object side 2 as well as an image-side surface facing toward the
image side 3. In addition, each object-side surface and image-side
surface in the optical imaging lens set 1 of the present invention
has a part in a vicinity of its circular periphery (circular
periphery part) away from the optical axis 4 as well as a part in a
vicinity of the optical axis (optical axis part) close to the
optical axis 4. For example, the first lens element 10 has a first
object-side surface 11 and a first image-side surface 12; the
second lens element 20 has a second object-side surface 21 and a
second image-side surface 22; the third lens element 30 has a third
object-side surface 31 and a third image-side surface 32; and the
fourth lens element 40 has a fourth object-side surface 41 and a
fourth image-side surface 42.
[0098] Each lens element in the optical imaging lens set 1 of the
present invention further has a central thickness on the optical
axis 4. For example, the first lens element 10 has a first lens
element thickness T1, the second lens element 20 has a second lens
element thickness T2, the third lens element 30 has a third lens
element thickness T3, and the fourth lens element 40 has a fourth
lens element thickness T4. Therefore, the total thickness of all
the lens elements in the optical imaging lens set 1 along the
optical axis 4 is ALT, ALT=T1+T2+T3+T4.
[0099] In addition, between two adjacent lens elements in the
optical imaging lens set 1 of the present invention there is an air
gap along the optical axis 4. For example, an air gap G12 is
disposed between the first lens element 10 and the second lens
element 20, an air gap G23 is disposed between the second lens
element 20 and the third lens element 30, and an air gap G34 is
disposed between the third lens element 30 and the fourth lens
element 40. Therefore, the sum of total three air gaps between
adjacent lens elements from the first lens element 10 to the fourth
lens element 40 along the optical axis 4 is Gaa,
Gaa=G12+G23+G34.
[0100] In addition, the distance between the object-side surface 11
of the first lens element 10 to the image plane 71 along the
optical axis 4 is TTL, namely the total length of the optical
imaging lens set.
First Example
[0101] Please refer to FIG. 1 which illustrates the first example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 2A for the longitudinal spherical aberration on the
image plane 71 of the first example; please refer to FIG. 2B for
the astigmatic field aberration on the sagittal direction; please
refer to FIG. 2C for the astigmatic field aberration on the
tangential direction, and please refer to FIG. 2D for the
distortion aberration. The Y axis of the spherical aberration in
each example is "field of view" for 1.0. The Y axis of the
astigmatic field and the distortion in each example stand for
"image height".
[0102] The optical imaging lens set 1 of the first example has four
lens elements 10 to 40, and all of the lens elements are made of a
plastic material and have refractive power. The optical imaging
lens set 1 also has an aperture stop 80, a filter 72, and an image
plane 71. The aperture stop 80 is provided between the first lens
element 10 and the second lens element 20. The filter 72 may be an
infrared filter (IR cut filter) to prevent inevitable infrared
light from reaching the image plane to adversely affect the imaging
quality.
[0103] The first lens element 10 has positive refractive power. The
first object-side surface 11 facing toward the object side 2 is a
convex surface, having a convex part 13 in the vicinity of the
optical axis and a convex part 14 in a vicinity of its circular
periphery; The first image-side surface 12 facing toward the image
side 3 is a convex surface, having a convex part 16 in the vicinity
of the optical axis and a convex part 17 in a vicinity of its
circular periphery.
[0104] The second lens element 20 has negative refractive power.
The second object-side surface 21 facing toward the object side 2
has a convex part 23 in the vicinity of the optical axis and a
convex part 24 in a vicinity of its circular periphery; The second
image-side surface 22 facing toward the image side 3 has a concave
part 26 in the vicinity of the optical axis and a concave part 27
in a vicinity of its circular periphery.
[0105] The third lens element 30 has positive refractive power. The
third object-side surface 31 facing toward the object side 2 is a
concave surface, having a concave part 33 in the vicinity of the
optical axis and a concave part 34 in a vicinity of its circular
periphery; The third image-side surface 32 facing toward the image
side 3 is a convex surface, having a convex part 36 in the vicinity
of the optical axis and a convex part 37 in a vicinity of its
circular periphery.
[0106] The fourth lens element 40 has negative refractive power.
The fourth object-side surface 41 facing toward the object side 2
has a convex part 43 in the vicinity of the optical axis and a
convex part 44 in a vicinity of its circular periphery; The fourth
image-side surface 42 facing toward the image side 3 has a concave
part 46 in the vicinity of the optical axis and a convex part 47 in
a vicinity of its circular periphery. The filter 72 may be disposed
between the fourth lens element 40 and the image plane 71.
[0107] In the optical imaging lens element 1 of the present
invention, the object-side surfaces 11/21/31/41 and image-side
surfaces 12/22/32/42 are all aspherical. These aspheric
coefficients are defined according to the following formula:
Z ( Y ) = Y 2 R / ( 1 + 1 - ( 1 + K ) Y 2 R 2 ) + i = 1 n a 2 i
.times. Y 2 i ##EQU00001##
[0108] In which:
[0109] R represents the curvature radius of the lens element
surface;
[0110] Z represents the depth of an aspherical surface (the
perpendicular distance between the point of the aspherical surface
at a distance Y from the optical axis and the tangent plane of the
vertex on the optical axis of the aspherical surface);
[0111] Y represents a vertical distance from a point on the
aspherical surface to the optical axis;
[0112] K is a conic constant; and
a2i is the aspheric coefficient of the 2i order.
[0113] The optical data of the first example of the optical imaging
lens set 1 are shown in FIG. 20 while the aspheric surface data are
shown in FIG. 21. In the present examples of the optical imaging
lens set, the f-number of the entire optical lens element system is
Fno, HFOV stands for the half field of view which is half of the
field of view of the entire optical lens element system, and the
unit for the curvature radius, the thickness and the focal length
is in millimeters (mm). The length of the optical imaging lens set
(the distance from the first object-side surface 11 of the first
lens element 10 to the image plane 71) is 4.550 mm. The image
height is 2.856 mm, HFOV is 37.273 degrees. Some important ratios
of the first example are shown in FIG. 36.
Second Example
[0114] Please refer to FIG. 3 which illustrates the second example
of the optical imaging lens set 1 of the present invention. It is
worth noting that from the second example to the following
examples, in order to simplify the figures, only the components
different from what the first example has and the basic lens
elements will be labeled in figures. Others components that are the
same as what the first example has, such as the object-side
surface, the image-side surface, the part in the vicinity of the
optical axis and the part in a vicinity of its circular periphery
will be omitted in the following example. Please refer to FIG. 4A
for the longitudinal spherical aberration on the image plane 71 of
the second example; please refer to FIG. 4B for the astigmatic
aberration on the sagittal direction; please refer to FIG. 4C for
the astigmatic aberration on the tangential direction, and please
refer to FIG. 4D for the distortion aberration. The components in
the second example are similar to those in the first example, but
the optical data such as the curvature radius, the refractive
power, the lens thickness, the lens focal length, the aspheric
surface or the back focal length in this example are different from
the optical data in the first example, and in this example, the
fourth object-side surface 41 of the fourth lens element 40 has a
concave part 44A in a vicinity of its circular periphery. The
optical data of the second example of the optical imaging lens set
are shown in FIG. 22 while the aspheric surface data are shown in
FIG. 23. The length of the optical imaging lens set is 4.542 mm.
The image height is 2.856 mm, HFOV is 36.1 degrees. Some important
ratios of the first example are shown in FIG. 36.
[0115] It is worth noting, compared with the first example, this
example has some advantages such as having larger aperture stop so
as to improve the dark shooting performance, being easier to
produce and having higher yield.
Third Example
[0116] Please refer to FIG. 5 which illustrates the third example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 6A for the longitudinal spherical aberration on the
image plane 71 of the third example; please refer to FIG. 6B for
the astigmatic aberration on the sagittal direction; please refer
to FIG. 6C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 6D for the distortion
aberration. The components in the third example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example, and in this example, the fourth object-side surface 41 of
the fourth lens element 40 has a concave part 44B in a vicinity of
its circular periphery. The optical data of the third example of
the optical imaging lens set are shown in FIG. 24 while the
aspheric surface data are shown in FIG. 25. The length of the
optical imaging lens set is 4.413 mm. The image height is 2.856 mm,
HFOV is 38.153 degrees. Some important ratios of the first example
are shown in FIG. 36.
[0117] It is worth noting, compared with the first example, this
example has some advantages such as having shorter total length,
having larger aperture stop, having larger HFOV to increase the
shooting range, having better imaging quality, being easier to
produce and having higher yield.
Fourth Example
[0118] Please refer to FIG. 7 which illustrates the fourth example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 8A for the longitudinal spherical aberration on the
image plane 71 of the fourth example; please refer to FIG. 8B for
the astigmatic aberration on the sagittal direction; please refer
to FIG. 8C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 8D for the distortion
aberration. The components in the fourth example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example. The optical data of the fourth example of the optical
imaging lens set are shown in FIG. 26 while the aspheric surface
data are shown in FIG. 27. The length of the optical imaging lens
set is 4.495 mm. The image height is 2.856 mm, HFOV is 37.408
degrees. Some important ratios of the first example are shown in
FIG. 36.
[0119] It is worth noting, compared with the first example, this
example has some advantages such as having shorter total length,
having larger aperture stop, having larger HFOV, having better
imaging quality, being easier to produce and having higher
yield.
Fifth Example
[0120] Please refer to FIG. 9 which illustrates the fifth example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 10A for the longitudinal spherical aberration on the
image plane 71 of the fifth example; please refer to FIG. 10B for
the astigmatic aberration on the sagittal direction; please refer
to FIG. 10C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 10D for the distortion
aberration. The components in the fifth example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example, and in this example, the fourth object-side surface 41 of
the fourth lens element 40 has a concave part 44C in a vicinity of
its circular periphery. The optical data of the fifth example of
the optical imaging lens set are shown in FIG. 28 while the
aspheric surface data are shown in FIG. 29. The length of the
optical imaging lens set is 4.003 mm. The image height is 2.856 mm,
HFOV is 36.656 degrees. Some important ratios of the first example
are shown in FIG. 36.
[0121] It is worth noting, compared with the first example, this
example has some advantages such as having larger aperture stop,
being easier to produce and having higher yield.
Sixth Example
[0122] Please refer to FIG. 11 which illustrates the sixth example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 12A for the longitudinal spherical aberration on the
image plane 71 of the sixth example; please refer to FIG. 12B for
the astigmatic aberration on the sagittal direction; please refer
to FIG. 12C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 12D for the distortion
aberration. The components in the sixth example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example, and in this example, the fourth object-side surface 41 of
the fourth lens element 40 has a concave part 44D in a vicinity of
its circular periphery. The optical data of the sixth example of
the optical imaging lens set are shown in FIG. 30 while the
aspheric surface data are shown in FIG. 31. The length of the
optical imaging lens set is 3.965 mm. The image height is 2.856 mm,
HFOV is 36.326 degrees. Some important ratios of the first example
are shown in FIG. 36.
[0123] It is worth noting, compared with the first example, this
example has some advantages such as having shorter total length,
having larger aperture stop, being easier to produce and having
higher yield.
Seventh Example
[0124] Please refer to FIG. 13 which illustrates the seventh
example of the optical imaging lens set 1 of the present invention.
Please refer to FIG. 14A for the longitudinal spherical aberration
on the image plane 71 of the seventh example; please refer to FIG.
14B for the astigmatic aberration on the sagittal direction; please
refer to FIG. 14C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 14D for the distortion
aberration. The components in the seventh example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example, and in this example, the third lens element 30 has
negative refractive power, the fourth lens element 40 has positive
power, and the fourth object-side surface 41 of the fourth lens
element 40 has a concave part 44E in a vicinity of its circular
periphery. The optical data of the seventh example of the optical
imaging lens set are shown in FIG. 32 while the aspheric surface
data are shown in FIG. 33. The length of the optical imaging lens
set is 4.003 mm. The image height is 2.856 mm, HFOV is 37.271
degrees. Some important ratios of the first example are shown in
FIG. 36.
[0125] It is worth noting, compared with the first example, this
example has some advantages such as having larger aperture stop,
being easier to produce and having higher yield.
Eighth Example
[0126] Please refer to FIG. 15 which illustrates the eighth example
of the optical imaging lens set 1 of the present invention. Please
refer to FIG. 16A for the longitudinal spherical aberration on the
image plane 71 of the eighth example; please refer to FIG. 16B for
the astigmatic aberration on the sagittal direction; please refer
to FIG. 16C for the astigmatic aberration on the tangential
direction, and please refer to FIG. 16D for the distortion
aberration. The components in the eighth example are similar to
those in the first example, but the optical data such as the
curvature radius, the refractive power, the lens thickness, the
lens focal length, the aspheric surface or the back focal length in
this example are different from the optical data in the first
example, and in this example, the third lens element 30 has
negative refractive power, the fourth lens element 40 has positive
power. The optical data of the eighth example of the optical
imaging lens set are shown in FIG. 34 while the aspheric surface
data are shown in FIG. 35. The length of the optical imaging lens
set is 3.999 mm. The image height is 2.856 mm, HFOV is 37.335
degrees. Some important ratios of the first example are shown in
FIG. 36.
[0127] It is worth noting, compared with the first example, this
example has some advantages such as having larger aperture stop,
having larger HFOV, being easier to produce and having higher
yield.
[0128] Following is the definitions of each parameter mentioned
above and some other parameters which are not disclosed in the
examples of the present invention, shown as TABLE 1:
TABLE-US-00001 TABLE 1 Parameter Definition T1 The thickness of the
first lens element along the optical axis G12 The distance between
the first lens element and the second lens element along the
optical axis T2 The thickness of the second lens element along the
optical axis G23 The distance between the second lens element and
the third lens element along the optical axis T3 The thickness of
the third lens element along the optical axis G34 The distance
between the third lens element and the fourth lens element along
the optical axis T4 The thickness of the fourth lens element along
the optical axis G4F The distance between the fourth image-side
surface of the fourth lens element to the filter along the optical
axis TF The thickness of the filter along the optical axis GFP The
distance between the filter to the image plane along the optical
axis f1 The focal length of the first lens element f2 The focal
length of the second lens element f3 The focal length of the third
lens element f4 The focal length of the fourth lens element n1 The
refractive index of the first lens element n2 The refractive index
of the second lens element n3 The refractive index of the third
lens element n4 The refractive index of the fourth lens element
.nu.1 The Abbe number of the first lens element .nu.2 The Abbe
number of the second lens element .nu.3 The Abbe number of the
third lens element .nu.4 The Abbe number of the fourth lens element
EFL The effective focal length of the optical imaging lens set TTL
The distance between the first object-side surface of the first
lens element to the image plane ALT The total thickness of all the
lens elements in the optical imaging lens set along the optical
axis Gaa The sum of total three air gaps between adjacent lens
elements from the first lens element to the fourth lens element
along the optical axis BFL The distance between the image-side
surface of the fourth lens element to the image plane along the
optical axis
[0129] The applicant summarized the efficacy of each embodiment
mentioned above as follows:
[0130] In the present invention, all of the longitudinal spherical
aberration, the astigmatism aberration and the distortion are in
compliance with the using standard (the longitudinal spherical
aberration is lower .+-.0.02 mm, the astigmatism aberration is
lower .+-.0.05 mm, and the distortion is lower .+-.2%). In
addition, the off-axis light of red, blue and green wavelengths are
focused on the vicinity of the imaging point in different height,
therefore the deviation between each off-axis light and the imaging
point is well controlled, so as to have good suppression for
spherical aberration, aberration and distortion. Furthermore, the
curves of red, blue and green wavelengths are very close to each
other, meaning that the dispersion on the axis has greatly improved
too. In summary, the different lens elements of the present
invention are matched to each other, to achieve good image
quality.
[0131] Furthermore, the optical imaging lens set 1 of the present
invention may be as short as about 4.6 mm. This ideal length allows
the dimensions and the size of the portable electronic device to be
smaller and lighter, but excellent optical performance and image
quality are still possible. In such a way, the various examples of
the present invention satisfy the need for economic benefits of
using fewer raw materials in addition to satisfying the trend for a
smaller and lighter product design and consumers' demands.
[0132] In addition, the inventors discover that there are some
better ratio ranges for different data according to the above
various important ratios. Better ratio ranges help the designers to
design the better optical performance and an effectively reduced
length of a practically possible optical imaging lens set. For
example:
[0133] (1) ALT/Gaa.gtoreq.2.0,
ALT/T1.gtoreq.3.5ALT/T2.gtoreq.6.2ALT/T3.gtoreq.3.0ALT/G34.ltoreq.25.0ALT-
/T4.ltoreq.4.5
[0134] With the development of optical technology, the length of
the optical imaging lens set becomes shorter, and ALT greatly
influences the total length of the optical imaging lens set. Even
if the thickness of the lens element can be changed according to
different materials, considering the difficulties of the
manufacturing process, ALT cannot be shrunk unlimitedly. Therefore,
in view of the unpredictability of the optical system design, when
those relationships mentioned above are satisfied, each example
will has a relative balance performance in imaging quality,
manufacturing yield and lens length. Preferably, if the
relationship ALT/Gaa.gtoreq.2.0 is satisfied, it is suggested
having the range between 2.0.about.3.0; If the relationship
ALT/T1.gtoreq.3.5 is satisfied, it is suggested having the range
between 3.5.about.5.0; If the relationship ALT/T2.gtoreq.6.2 is
satisfied, it is suggested having the range between 6.2.about.10.0;
If the relationship ALT/T3.gtoreq.3.0 is satisfied, it is suggested
having the range between 3.0.about.5.0; If the relationship
ALT/G34.ltoreq.25.0 is satisfied, it is suggested having the range
between 10.0.about.25.0; If the relationship ALT/T4.ltoreq.4.5 is
satisfied, it is suggested having the range between
2.0.about.4.5.
[0135] (2)
Gaa/G12.ltoreq.12.0Gaa/G23.ltoreq.1.5Gaa/T1.gtoreq.1.2Gaa/T2.gt-
oreq.3.0 Gaa/T3.gtoreq.1.0:
[0136] Gaa is the sum of total air gaps between adjacent lens
elements along the optical axis, and greatly influences the
assembly yield of the optical imaging lens set. Under the recent
manufacturing technologies, the optical imaging lens set is
difficult to be assembled if Gaa is too small, while the total
length will become too long if Gaa is too big. Therefore, in view
of the unpredictability of the optical system design, when those
relationships mentioned above are satisfied, each example will has
a relative balance performance in manufacturing yield and lens
length. Preferably, if the relationship Gaa/G12.ltoreq.12.0 is
satisfied, it is suggested having the range between 7.0.about.12.0;
If the relationship Gaa/G23.ltoreq.1.5 is satisfied, it is
suggested having the range between 1.0.about.1.5; If the
relationship Gaa/T1.gtoreq.1.2 is satisfied, it is suggested having
the range between 1.2.about.2.0; If the relationship
Gaa/T2.gtoreq.3.0 is satisfied, it is suggested having the range
between 3.0.about.4.0; If the relationship Gaa/T3.gtoreq.1.0 is
satisfied, it is suggested having the range between
1.0.about.2.0.
[0137] (3) TTL/ALT.gtoreq.1.8 TTL/G12.ltoreq.55.0
TTL/G23.ltoreq.8.0 TTL/Gaa.ltoreq.6.0
TTL/T1.ltoreq.7.0TTL/T2.ltoreq.15.0TTL/T3.ltoreq.9.0
TTL/T4.ltoreq.9.5
[0138] With the development of optical technology, the total length
of the optical imaging lens set becomes shorter. But considering
the difficulties of manufacturing process, TTL cannot be shrunk
unlimitedly. Therefore, in view of the unpredictability of the
optical system design, when those relationships mentioned above are
satisfied, each example will has a relative balance performance in
imaging quality and lens length. Preferably, if the relationship
TTL/ALT.gtoreq.1.8 is satisfied, it is suggested having the range
between 1.8.about.2.5; If the relationship TTL/G12.ltoreq.55.0 is
satisfied, it is suggested having the range between
40.0.about.55.0; If the relationship TTL/G23.ltoreq.8.0 is
satisfied, it is suggested having the range between 5.0.about.8.0;
If the relationship TTL/Gaa.ltoreq.6.0 is satisfied, it is
suggested having the range between 4.0.about.6.0; If the
relationship TTL/T1.gtoreq.7.0 is satisfied, it is suggested having
the range between 7.0.about.10.0; If the relationship
TTL/T2.gtoreq.15.0 is satisfied, it is suggested having the range
between 15.0.about.20.0; If the relationship TTL/T3.ltoreq.9.0 is
satisfied, it is suggested having the range between 5.0.about.9.0;
If the relationship TTL/T4.ltoreq.9.5 is satisfied, it is suggested
having the range between 4.0.about.9.5.
[0139] The optical imaging lens set 1 of the present invention may
be applied to a portable electronic device. Please refer to FIG.
18. FIG. 18 illustrates a first preferred example of the optical
imaging lens set 1 of the present invention for use in a portable
electronic device 100. The portable electronic device 100 includes
a case 110, and an image module 120 mounted in the case 110. A
mobile phone is illustrated in FIG. 16 as an example, but the
portable electronic device 100 is not limited to a mobile
phone.
[0140] As shown in FIG. 18, the image module 120 includes the
optical imaging lens set 1 as described above. FIG. 18 illustrates
the aforementioned first example of the optical imaging lens set 1.
In addition, the portable electronic device 100 also contains a
barrel 130 for the installation of the optical imaging lens set 1,
a module housing unit 140 for the installation of the barrel 130, a
substrate 172 for the installation of the module housing unit 140
and an image sensor 70 disposed at the substrate 172, and at the
image side 3 of the optical imaging lens set 1. The image sensor 70
in the optical imaging lens set 1 may be an electronic
photosensitive element, such as a charge coupled device or a
complementary metal oxide semiconductor element. The image plane 71
forms at the image sensor 70.
[0141] The image sensor 70 used here is a product of chip on board
(COB) package rather than a product of the conventional chip scale
package (CSP) so it is directly attached to the substrate 172, and
protective glass is not needed in front of the image sensor 70 in
the optical imaging lens set 1, but the present invention is not
limited to this.
[0142] To be noticed in particular, the optional filter 72 may be
omitted in other examples although the optional filter 72 is
present in this example. The case 110, the barrel 130, and/or the
module housing unit 140 may be a single element or consist of a
plurality of elements, but the present invention is not limited to
this.
[0143] Each one of the four lens elements 10, 20, 30 and 40 with
refractive power is installed in the barrel 130 with air gaps
disposed between two adjacent lens elements in an exemplary way.
The module housing unit 140 has a lens element housing 141, and an
image sensor housing 146 installed between the lens element housing
141 and the image sensor 70. However in other examples, the image
sensor housing 146 is optional. The barrel 130 is installed
coaxially along with the lens element housing 141 along the axis
I-I', and the barrel 130 is provided inside of the lens element
housing 141.
[0144] Please also refer to FIG. 19 for another application of the
aforementioned optical imaging lens set 1 in a portable electronic
device 200 in the second preferred example. The main differences
between the portable electronic device 200 in the second preferred
example and the portable electronic device 100 in the first
preferred example are: the lens element housing 141 has a first
seat element 142, a second seat element 143, a coil 144 and a
magnetic component 145. The first seat element 142 is for the
installation of the barrel 130, exteriorly attached to the barrel
130 and disposed along the axis I-I'. The second seat element 143
is disposed along the axis I-I' and surrounds the exterior of the
first seat element 142. The coil 144 is provided between the
outside of the first seat element 142 and the inside of the second
seat element 143. The magnetic component 145 is disposed between
the outside of the coil 144 and the inside of the second seat
element 143.
[0145] The first seat element 142 may pull the barrel 130 and the
optical imaging lens set 1 which is disposed inside of the barrel
130 to move along the axis I-I', namely the optical axis 4 in FIG.
1. The image sensor housing 146 is attached to the second seat
element 143. The filter 72, such as an infrared filter, is
installed at the image sensor housing 146. Other details of the
portable electronic device 200 in the second preferred example are
similar to those of the portable electronic device 100 in the first
preferred example so they are not elaborated again.
[0146] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *